Pretty straightforward. $10 for a $15 iTunes Code from Groupon, limited quantities available, limit one per person. If you buy iTunes music, iPhone apps, Mac apps, or even TV shows or books in the App Store, save yourself five bucks. Code arrives within minutes, ready to apply to your account.
From 8/29-9/1 also get an extra 10% off Groupon Goods with coupon code LABOR10.